const base64 = {
  _keyStr: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=',
  encode: function (e) {
    var t = ''
    var n, r, i, s, o, u, a
    var f = 0
    e = base64._utf8_encode(e)
    while (f < e.length) {
      n = e.charCodeAt(f++)
      r = e.charCodeAt(f++)
      i = e.charCodeAt(f++)
      s = n >> 2
      o = ((n & 3) << 4) | (r >> 4)
      u = ((r & 15) << 2) | (i >> 6)
      a = i & 63
      if (isNaN(r)) {
        u = a = 64
      } else if (isNaN(i)) {
        a = 64
      }
      t =
        t +
        this._keyStr.charAt(s) +
        this._keyStr.charAt(o) +
        this._keyStr.charAt(u) +
        this._keyStr.charAt(a)
    }
    return t
  },
  decode: function (e) {
    var t = ''
    var n, r, i
    var s, o, u, a
    var f = 0
    e = e.replace(/[^A-Za-z0-9+/=]/g, '')
    while (f < e.length) {
      s = this._keyStr.indexOf(e.charAt(f++))
      o = this._keyStr.indexOf(e.charAt(f++))
      u = this._keyStr.indexOf(e.charAt(f++))
      a = this._keyStr.indexOf(e.charAt(f++))
      n = (s << 2) | (o >> 4)
      r = ((o & 15) << 4) | (u >> 2)
      i = ((u & 3) << 6) | a
      t = t + String.fromCharCode(n)
      if (u != 64) {
        t = t + String.fromCharCode(r)
      }
      if (a != 64) {
        t = t + String.fromCharCode(i)
      }
    }
    t = base64._utf8_decode(t)
    return t
  },
  _utf8_encode: function (e) {
    e = e.replace(/rn/g, 'n')
    var t = ''
    for (var n = 0; n < e.length; n++) {
      var r = e.charCodeAt(n)
      if (r < 128) {
        t += String.fromCharCode(r)
      } else if (r > 127 && r < 2048) {
        t += String.fromCharCode((r >> 6) | 192)
        t += String.fromCharCode((r & 63) | 128)
      } else {
        t += String.fromCharCode((r >> 12) | 224)
        t += String.fromCharCode(((r >> 6) & 63) | 128)
        t += String.fromCharCode((r & 63) | 128)
      }
    }
    return t
  },
  _utf8_decode: function (e) {
    var t = ''
    var n = 0
    var r = (c1 = c2 = 0)
    while (n < e.length) {
      r = e.charCodeAt(n)
      if (r < 128) {
        t += String.fromCharCode(r)
        n++
      } else if (r > 191 && r < 224) {
        c2 = e.charCodeAt(n + 1)
        t += String.fromCharCode(((r & 31) << 6) | (c2 & 63))
        n += 2
      } else {
        c2 = e.charCodeAt(n + 1)
        c3 = e.charCodeAt(n + 2)
        t += String.fromCharCode(
          ((r & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63)
        )
        n += 3
      }
    }
    return t
  }
}
export { base64 }
